1. Field of the Invention
The present invention relates to a solid-state imaging apparatus using a CCD-based solid-state imaging device or the like. Particularly, the invention relates to a solid-state imaging apparatus in which a solid-state imaging device produces an image signal based on the summation of signal charges of two adjacent lines, and is driven such that the two adjacent lines of the alternately-consecutive first and second fields are equal, thereby obtaining a sequentially-scanned video signal without using an expensive scanning converter, etc.
2. Description of the Prior Art
FIG. 1 shows the arrangement of a conventional system for producing a sequentially-scanned video signal. The system consists of a CCD-based solid-state imaging device 101 which produces a skip-scanned video signal SVi, and a scanning converter 102 which processes the skip-scanned video signal SVi to produce a sequentially-scanned video signal SVn.
FIG. 2 shows the arrangement of the scanning converter 102. The scanning converter 102 has an input terminal 121 on which the skip-scanned video signal SVi is supplied, a line memory 122 which delays the input video signal SVi by one horizontal period, and an adder 123 and factor operator 124 by which the input video signal SVi and the delayed video signal provided by the line memory 122 are summed and averaged into a video signal SVa.
The scanning converter 102 further includes a switch circuit 125 which selects the input video signal SVi or the video signal SVa provided by the factor operator 124, and an output terminal 126 which releases the output video signal provided by the switch circuit 125. The factor operator 124 has its output connected to the a-input terminal of the switch circuit 125, and the input terminal 121 is connected to the b-input terminal of the switch circuit 125. The switch circuit 125 is supplied with a switch control signal SW, and it turns to select its a-input or b-input in correspondence to the alternately-consecutive first and second fields of the video signal SVi in response to the signal SW.
In one case, the system receives the skip-scanned video signal SVi on the input terminal 121. FIG. 3A shows line signals of the video signal SVi, with the solid lines and dashed lines signifying the line signals of the first field and second field, respectively. For the first field, the switch circuit 125 selects its b-input to provide as sequentially-scanned video signal SVn the first frame signal (shown in FIG. 3B) derived from a line signal of the video signal SVi. For the second field, the switch circuit 125 selects its a-input to provide as sequentially-scanned video signal SVn the second frame signal (shown in FIG. 3C) derived from a line signal of the video signal SVa. The sequentially-scanned video signal SVn is output from the output terminal 126.
This conventional system shown in FIG. 1 has a problem of needing an expensive scanning converter 102, which includes a line memory 122 as shown in FIG. 2, for producing the sequentially-scanned video signal SVn.